I am telling you though, at some institutions (my own included) that is unfortunately not the case. The culture here is equal parts New York and Ivy, and so probably a Perfect Storm of pretentiousness, but people really do stack each other up by pedigree. They can't fathom a world in which people don't put equal stock into the names of schools. They can't fathom why someone wouldn't have attended a top 10 medical school, or an Ivy college, or an exclusive prep school, or the right feeder preschool, unless they couldn't get in. And if you couldn't get in, that means you obviously aren't as good as the people who did get in.
Not justifying this in any way, but you will encounter prejudice at certain places. Let it roll off your back like water. It does come up, throughout residency-- I've seen uncomfortable jokes made about the training background of even senior/chief residents.